preeti Verma - Academia.edu (original) (raw)

Papers by preeti Verma

Bioresource Technology, 2009

A controlled and up-scalable route for the biosynthesis of silver nanopartilces (NPs) mediated by... more A controlled and up-scalable route for the biosynthesis of silver nanopartilces (NPs) mediated by fungal proteins of Coriolus versicolor has been undertaken for the first time. The fungus when challenged with silver nitrate solution accumulated silver NPs on its surface in 72 h which could be reduced to 1 h by tailoring the reaction conditions. Under alkaline conditions, the reaction was much faster and could easily proceed at room temperature even without stirring. The resulting Ag NPs displayed controllable structural and optical properties depending on the experimental parameters such as pH and reaction temperatures. The average size, morphology, and structure of particles were determined by AFM, TEM, XRD and UV/Visible absorption spectrophotometry. Fourier transform infrared study disclosed that the amino groups were bound to the particles, which was accountable for the stability of NPs. It further confirmed the presence of protein as the stabilizing and capping agent surrounding the silver NPs. Experiments were conducted both with, media in which fungus was initially harvested and that of pristine fungal mycelium alone. Under normal conditions, in the case of media extracellular synthesis took place whereby other than the fungal proteins, glucose was also responsible for the reduction. In the case of fungal mycelium, the intracellular formation of Ag NPs, could be tailored to give both intracellular and extracellular Ag NPs under alkaline conditions whereby the surface S-H groups of the fungus played a major role.

Journal of Environmental Sciences-china, 2009

The present study evaluated the potential of white-rot fungal strain Coriolus versicolor to decol... more The present study evaluated the potential of white-rot fungal strain Coriolus versicolor to decolorize five structurally different dyes in sequential batch reactors under optimized conditions. The experiments were run continuously for seven cycles of 8 d each. High decolorizing activity was observed even during the repeated reuse of the fungus, especially when the old medium was replaced with fresh medium after every cycle. Biodegradation was the dominating factor as the fungus was able to produce the enzyme laccase mainly, to mineralize synthetic dyes. The nutrients and composition of the medium played important roles in sustaining the decolorisation potential of the fungus. Corncob was found be an easy and cheap substitute for carbon source for the fungus. Glucose consumption by the fungus was in accordance to its decolorisation activity and chemical oxygen demand (COD) reduction.

Chemical Engineering Journal, 2009

A novel "green" route to prepare CdS nanoparticles under ambient conditions is reported. The long... more A novel "green" route to prepare CdS nanoparticles under ambient conditions is reported. The long-term studies were carried out with immobilized fungus Coriolus versicolor in continuous column mode. The immobilized fungus served a dual purpose of both bioremediating cadmium as well as synthesizing stable CdS nanoparticles in aqueous conditions. The fungus immobilized in the column could remove 98% cadmium within 2 h. The continuous and extracelluar production of autocapped CdS nanoparticles is an added advantage of this system. Interestingly, no external source of sulfur is required for the transformation of toxic Cd to non-toxic CdS. The thiol group of the fungal protein was found mainly responsible for the production of such highly stable and autocapped CdS nanoparticles. The physico-chemical properties of the particles were studied by FTIR, XRD, SEM, TEM, AFM, TGA and PL.

Process Safety and Environmental Protection, 2011

The ability of the white rot fungus Coriolus versicolor, to produce enzymes during its growth and... more The ability of the white rot fungus Coriolus versicolor, to produce enzymes during its growth and decolorise five chemically different sulphonic azo synthetic dyes was evaluated under the operating conditions which had already been optimized. An increase in the initial dye content, led to a slow decrease in the decolorisation efficiency. Sequential batch culture studies were performed in the laboratory

Bioresource Technology, 2009

A controlled and up-scalable route for the biosynthesis of silver nanopartilces (NPs) mediated by... more A controlled and up-scalable route for the biosynthesis of silver nanopartilces (NPs) mediated by fungal proteins of Coriolus versicolor has been undertaken for the first time. The fungus when challenged with silver nitrate solution accumulated silver NPs on its surface in 72 h which could be reduced to 1 h by tailoring the reaction conditions. Under alkaline conditions, the reaction was much faster and could easily proceed at room temperature even without stirring. The resulting Ag NPs displayed controllable structural and optical properties depending on the experimental parameters such as pH and reaction temperatures. The average size, morphology, and structure of particles were determined by AFM, TEM, XRD and UV/Visible absorption spectrophotometry. Fourier transform infrared study disclosed that the amino groups were bound to the particles, which was accountable for the stability of NPs. It further confirmed the presence of protein as the stabilizing and capping agent surrounding the silver NPs. Experiments were conducted both with, media in which fungus was initially harvested and that of pristine fungal mycelium alone. Under normal conditions, in the case of media extracellular synthesis took place whereby other than the fungal proteins, glucose was also responsible for the reduction. In the case of fungal mycelium, the intracellular formation of Ag NPs, could be tailored to give both intracellular and extracellular Ag NPs under alkaline conditions whereby the surface S-H groups of the fungus played a major role.

Journal of Environmental Sciences-china, 2009

The present study evaluated the potential of white-rot fungal strain Coriolus versicolor to decol... more The present study evaluated the potential of white-rot fungal strain Coriolus versicolor to decolorize five structurally different dyes in sequential batch reactors under optimized conditions. The experiments were run continuously for seven cycles of 8 d each. High decolorizing activity was observed even during the repeated reuse of the fungus, especially when the old medium was replaced with fresh medium after every cycle. Biodegradation was the dominating factor as the fungus was able to produce the enzyme laccase mainly, to mineralize synthetic dyes. The nutrients and composition of the medium played important roles in sustaining the decolorisation potential of the fungus. Corncob was found be an easy and cheap substitute for carbon source for the fungus. Glucose consumption by the fungus was in accordance to its decolorisation activity and chemical oxygen demand (COD) reduction.

Chemical Engineering Journal, 2009

A novel "green" route to prepare CdS nanoparticles under ambient conditions is reported. The long... more A novel "green" route to prepare CdS nanoparticles under ambient conditions is reported. The long-term studies were carried out with immobilized fungus Coriolus versicolor in continuous column mode. The immobilized fungus served a dual purpose of both bioremediating cadmium as well as synthesizing stable CdS nanoparticles in aqueous conditions. The fungus immobilized in the column could remove 98% cadmium within 2 h. The continuous and extracelluar production of autocapped CdS nanoparticles is an added advantage of this system. Interestingly, no external source of sulfur is required for the transformation of toxic Cd to non-toxic CdS. The thiol group of the fungal protein was found mainly responsible for the production of such highly stable and autocapped CdS nanoparticles. The physico-chemical properties of the particles were studied by FTIR, XRD, SEM, TEM, AFM, TGA and PL.

Process Safety and Environmental Protection, 2011

The ability of the white rot fungus Coriolus versicolor, to produce enzymes during its growth and... more The ability of the white rot fungus Coriolus versicolor, to produce enzymes during its growth and decolorise five chemically different sulphonic azo synthetic dyes was evaluated under the operating conditions which had already been optimized. An increase in the initial dye content, led to a slow decrease in the decolorisation efficiency. Sequential batch culture studies were performed in the laboratory